Abstract:
Soil-borne fungus pathogens exist in soil, water, or in or on infected roots. Fungi may also reside in crown and foliar tissue as both mycelium, spores or resting structures such as sclerotia of chlamydospores. Spores or resting structures may be transmitted by tools, equipment, pots, benches, flats, shoes or any other items that may harbor bits of infested soil.

Fungus propagules may be disseminated in water used for irrigation, in soil used in containers, and with soil particles splashed, blown, or otherwise moved to susceptible plants. Soil insects may also transmit pathogenic soil-borne fungi. Soil-borne fungi commonly invade plants at or below the soil line and disease development begins before top symptoms are detected. During prolonged periods of high humidity accompanied by splashing water, fungi such as Phytopthora, Rhizoctonia, Cylindrocladium, Sclerotium and Pythium infect and colonize stems, petioles and occasionally leaf tissue. The youngest tissues are